1. Field of the Invention
The present invention relates to the fabrication of integrated circuit devices, and more particularly, to a method of improving the gap filling characteristics of an ozone-TEOS dielectric layer in the fabrication of integrated circuits.
2. Description of the Prior Art
Ozone-tetraethoxysilane (O.sub.3 -TEOS) is often used as a dielectric layer overlying a patterned metal layer. Since, O.sub.3 -TEOS is moisture absorptive, a dense and good quality plasma-enhanced chemically vapor deposited (PECVD) oxide (PE-OX) is usually deposited prior to O.sub.3 -TEOS deposition to prevent moisture penetration into the underlying devices. The underlayer also provides a uniform nucleation layer, reduces poisoned via problems, inhibits cracking, and suppresses hillock formation. However, because of the poor step coverage of PE-OX, voids form within the overlying O.sub.3 -TEOS layer within narrow gaps between features on the semiconductor substrate surface.
Related patent application Ser. No. 08/494,630, (TS94-098) to the same inventors improves the gap-filling capability of ozone-TEOS by using an underlayer composed of both PE-OX and PE-TEOS.